1. Technical Field
The present invention relates to an apparatus for driving an occupant-protecting airbag device mounted on a vehicle.
2. Related Art
At present, a variety of types of on-vehicle occupant-protecting airbag systems have been known. Of these, one type of on-vehicle occupant-protecting airbag system is proposed by a patent publication No. 2001-505151.
This system is provided with an ignition circuit, a plurality of acceleration sensors, a single A/D converter, and a logic circuit. Each of the acceleration sensors is in charge of not only sensing various types of acceleration acting on an automobile but also generating analog electrical signals, each indicative of an amount of each type of acceleration. The A/D converter is placed to convert the analog electrical signals detected from the acceleration sensors into corresponding digital electrical signals. The logic circuit generates control signals to drive the ignition circuit in response to the A/D-converted digital detection signals.
The on-vehicle airbag system should be deployed in an emergency, but should not be easily deployed when the vehicle is in a normal state. To prevent the airbag from being deployed in the normal state, the airbag system is usually provided with devices for the prevention. One of such devices is a circuit that allows an airbag to be inflated only when all of a plurality of acceleration sensors installed in the system sense accelerations and generates ON signals.
However, the conventional on-vehicle airbag system has only one A/D converter as exemplified by the foregoing reference, there is a fear that use of such a single A/D converter invites undesirable situations. That is, when the single A/D converter operates erroneously due to such a disorder or some other malfunction, such a fear may be unfortunately realized.